Add color to Go log output

For terminal output, ANSI escape sequences are the simplest option: \033[31m selects red, \033[32m green, and \033[0m resets formatting. Libraries such as Logrus and charmbracelet/log can handle terminal formatting for you.

Write ANSI sequences directly

package main

import "fmt"

const (
    colorRed    = "\033[31m"
    colorGreen  = "\033[32m"
    colorYellow = "\033[33m"
    colorReset  = "\033[0m"
)

func main() {
    fmt.Println(colorRed + "ERROR: connection failed" + colorReset)
    fmt.Printf("%sINFO%s: startup complete\n", colorGreen, colorReset)
}

Always reset the formatting so later terminal output does not inherit the color.

Use Logrus

Configure its text formatter inside your application:

log.SetFormatter(&log.TextFormatter{ForceColors: true})
log.Warn("Warning message")

Here log refers to github.com/sirupsen/logrus. ForceColors: true forces color even when the output is not a terminal. Omit that setting to use the formatter's normal terminal detection, or set DisableColors: true for a plain-text destination.

Use a handler with slog

Go 1.21 introduced log/slog. Its built-in text and JSON handlers do not add color. A compatible third-party handler, such as charmbracelet/log, can provide terminal styling while retaining structured attributes.

Keep collected logs plain

Disable color when writing to files or forwarding logs to a collector. Otherwise, the escape bytes become part of the stored message. Terminal support depends on the terminal host and its configuration; running PowerShell alone does not guarantee ANSI rendering on every Windows console.

How can I clean up existing color codes?

A pattern such as \x1b\[[0-9;]*m removes common SGR color sequences. It is not a general ANSI parser and does not cover every terminal-control sequence. Preventing the codes at the logger is preferable.

See the Logrus formatter documentation and Charm log documentation for their handler options.